This invention relates to step and repeat apparatus of the kind used for performance of operations upon an approximately planar component. Such a component may be one of a large number each having features located in a not necessarily regular array on the planar surface. The apparatus may be used for performing operations repeatedly on successive components. Examples of step and repeat apparatus include microprocessor wafer probes, printed circuit manufacturing apparatus laser trimmers and other apparatus for manufacture of hybrid circuits.
Wafer probe apparatus is required to move and accurately position a wafer in relation to a probe head. Once in position the wafer is raised into contact with the probe. Conventional apparatus comprises a first bed accurately movable in a first dimension, a second bed mounted upon the first and accurately movable in a second perpendicular dimension and a support located upon the second bed. The support is raised by a lifting mechanism when the wafer is brought into contact with the probe.
The lifting mechanism is relatively sophisticated since it must raise the whole wafer a precise amount for performance of an operation upon the wafer. The position of the wafer is observed by use of a microscope. Difficulties in design arise in arranging for the microscope, beds and lifting mechanism to fit in the distance between a seated user's knees and eyes.
According to the present invention step and repeat apparatus comprises a support for a workpiece and an arm, the support being attached by means of the arm to a mechanism adapted to move the support in two dimensions, the arm being pivotally secured to said mechanism at a location remote from the support, the apparatus further comprising lifting means arranged to move the support about the pivot in a plane perpendicular to said two dimensions.
The lifting means may be remote from the said mechanism. Furthermore the mechanism is preferably not located beneath the microscope, reducing the knee-to-eye distance of the apparatus.
Avoidance of the need for stacking the said mechanism confers great advantage. The lifting mechanism may have a simple, lightweight design. The mechanism does not need to include relatively massive beds which are rigid to support the lifting mechanism. The mechanism may be concealed beneath a dust cover, whereas beds movable with the workpiece are difficult to cover. In addition concealment of the mechanism reduces noise. Furthermore, access to the workpiece is facilitated, for example for wafer handling apparatus, laser marking devices, probes, line width measurement devices etc. Manufacture of the apparatus is much easier with consequent savings in costs.
The invention is further described by means of example and not in any limitative sense.